Field of the Invention
The present invention relates to a numerical control device for controlling machining operations for machining workpieces to be machined with tools and auxiliary operations for assisting the machining operations, and also relates to a control method for the numerical control device.
Description of the Related Art
A numerical control device of a machine tool performs machining operations such as cutting, polishing, etc., of a workpiece while axially moving a tool and also performs subsidiary operations (auxiliary operations) for machining operations. Examples of auxiliary operations include tool changes, workpiece replacement and supply/suspension of cutting oil. By performing auxiliary operations of this kind in advance during machining operations as necessary, it is possible to shorten the processing time (cycle time) for the entire workpiece machining process.
For this reason, the numerical control device decides implementation of auxiliary operations by looking-ahead the machining program. For example, the numerical control device disclosed in Japanese Patent No. 5210070 includes a first machining program analyzer for analyzing the entire machining program and a second machining program analyzer for analyzing auxiliary operations alone in the machining program. Then, the auxiliary operations analyzed by the second program analyzer are performed in advance to thereby shorten the processing time.